[damien c]

To get true high definition sound iirc you would need a 7.1 surround sound set up, which again iirc is only going to be found on some blu-ray film's.

The digital output as zing said will be a line out socket on your laptop, but that will also act as a S/PDIF output as well, with a little adaptor that should have come in the box of goodies with the laptop.

Other than that you could always just buy a 5.1 cinema system that has a phono connection input, and get a 3.5m to phono cable for your laptop and then iirc if it comes with a dvd/blu-ray player, and you connect it to your tv all the tv sound will come through the speaker's of the surround sound system.

The other way to do it is to get a cinema system, that connects to your tv then you connect your laptop to your tv, and connect the sound output of the laptop to the tv then the sound from the laptop should come through the 5.1 cinema system.